Older adults with severe hearing loss are more likely to have dementia, according to a study by researchers at the Johns Hopkins Bloomberg School of Public Health, but dementia cases were lower among study participants who used hearing aids.
What have we learned?
Previous studies have also found a link between hearing loss and dementia. A study published in 2012 found that compared to people with normal hearing, people with mild hearing loss had twice the risk of developing dementia, people with moderate hearing loss had three times the risk, and people with severe hearing loss had five times the risk. high risk of dementia. develop dementia. It is estimated that hearing loss accounts for 8% of dementia cases worldwide – more than any other potentially modifiable risk factor for dementia, according to the Lancet Commission on Dementia Prevention, Intervention and Care.
But researchers from this latest study, whose findings were published Jan. 10 in a research letter in the peer-reviewed journal JAMA, say previous studies were limited because they were “vulnerable to selection bias” — using self-reported data that may not have been accurate. picture of hearing loss and dementia on a national scale.
“This study used an objective, audiometric measurement of hearing rather than relying on subjective, self-reported hearing loss. We also used data that has a greater representation of older adults in the US,” said Alison Huang, the study’s lead author and a senior research fellow at the Cochlear Center for Hearing and Public Health, in an email to Yahoo News.
The study, funded by the National Institute on Aging, analyzed a national dataset from the National Health and Aging Trends Study, which has been running since 2011.
“The National Health and Aging Trends Study collects data through home visits, making it easier for more vulnerable populations, such as adults over the age of 90 and older adults with disabilities, to participate compared to a clinical trial, which only captures people who have the ability and resources to go to clinics,” Huang said.
The analysis of this study included 2,413 individuals, about half of whom were over the age of 80, and “showed a clear association between severity of hearing loss and dementia,” according to a Johns Hopkins press release. Among participants with “moderate/severe hearing loss”, the prevalence of dementia was 61% higher than among participants with normal hearing.
The good news?
The good news is that hearing aids may have an additional benefit. The study found that of 853 participants with moderate to severe hearing loss, “hearing aid use was associated with a 32% lower prevalence of dementia.”
“We are encouraged to see a link between hearing aid use and a lower prevalence of dementia, building support for public health measures to improve access to hearing care,” Huang told Yahoo News.
She added that more work is needed from randomized trials to definitively test the effect of hearing aids on cognition and dementia. The ACHIEVE (Aging and Cognitive Health Evaluation in Elsewhere) study, also funded by the National Institute on Aging, is testing the effect of hearing loss treatment on cognition and dementia, and results from that study will be available later this year, he said. Huang.
About one-third of older adults have hearing loss, and the likelihood of developing hearing loss increases with age, according to the National Institute on Aging.
Dr. Frank Lin, one of the leaders of the ACHIEVE study, has cited several possible reasons for the link between hearing loss and cognitive decline. Hearing loss “can cause the brain to work harder”, straining hearing at the expense of memory systems; hearing loss can also cause the brain to “shrink faster.” Another possible reason is that hearing loss can cause people to become more socially isolated, which harms brain health.
“If you can’t hear very well, maybe you don’t go out as much,” Lin said, “so the brain is less engaged and active.”